Closing system and electronic control method

ABSTRACT

A closing system is described and a correspondingly suitable method for the selective opening and closing of a tubular body organ, comprising a closing element and a regulating system controlling the closing element. Furthermore described are a method and a system for the electronic control of an artificial fine-sensory sphincter implant, with at least one sensor signal or, respectively, sensor value acting—in the method or, respectively, in the system—analog to the difference between the internal bladder pressure and the cuff pressure, and being converted in an analog or digital electronic circuit by means of calculator and comparator functions or, respectively, calculator and comparator elements and being compared with reference values such that an actuator system will be controlled such that the cuff pressure or, respectively, the differential pressure between cuff and urinary bladder moves either in a low area limited by two threshold values or above a specific safety pressure or below that in case of miction.

The following invention relates to a closing system and acorrespondingly suitable method for the selective opening and closing ofa tubular body organ.

From DE 43 31 658, an implantable device for the selective opening andclosing of tubular body organs is known, with an elongated valve bodybeing provided which is insertable into the tubular body organ. Thevalve body has a shutoff device which can be selectively closed andreleased. To this end, the valve body has an elastic hose section inwhich an inflatable body is arranged which is inflatable by a fluid andthen closes the lumen of the hose section. Opening as well as closing isdone by manual handling, i.e. inflation of the inflatable body is doneby manual operation of a pump and opening is by manual operation of aswitch. In principle, however, it must be taken care, with the knownsystem, that the inflatable body will not be inflated so much that, onthe one hand, the bodily organ will also enlarge and expand as a resultof the frequent opening and closing, and on the other hand, the pressuregenerated by the inflatable body would cut the blood circulation of thebody organ so that the tissue of the body organ would necrotize. Thus,these specifications require that closing the body organ with the knownsystem is only possible within a limited pressure range; however,developing pressure peaks or, respectively, short-term pressure loadsor, respectively, pressure increases in the body organ cannot ensure asecure closing of the body organ since the known system is not suitablefor short-term following.

Accordingly, one objective of the present invention is to furtherdevelop the known closing system or, respectively, the known method forthe selective opening and closing of a tubular body organ such that anypressure increases in the body organ to be closed will be counteractedshort-term and the risk of necrosis will be nearly excluded.

Another objective of the present invention is to provide a closingsystem which ensures continence at any time.

These objectives are solved by the technical device with thecharacteristics of Claim 1 and by the technical method with thecharacteristics of Claim 9.

In accordance with the application, the closing system or, respectively,the method according to the invention for the selective opening andclosing of a tubular body organ provides a closing element and aregulating system controlling the closing element, with the regulatingsystem setting a first condition of the closing system and returning, ina self-regulating manner, a deviation from the first condition back tothe first condition. This measure in accordance with the applicationwill achieve that—with pressure peaks or, respectively, pressure loadsoccurring due to coughing, sneezing, laughing or bending over—therequired objectives of the closing system can still be met. For example,if the closing system is applied at the urethra, this measure inaccordance with the application can provide a sphincter replacementsystem which replaces the function of the outer sphincter of the urethrain adult humans. Thus, the closing system in accordance with theapplication can be used as an implantable adaptive fine-sensorysphincter replacement system. Due to the fact that a first condition ofthe regulating system will be left only for a short time because ofpressure peaks, the risk of necrosis can be reduced and, respectively,necrotic phenomena can be prevented. With the closing system inaccordance with the application will thus be prevented that a constantlyhigh closing pressure acts upon the body organ or, respectively, theurethra which would cause the surrounding body organ tissue to developnecrosis or inflammations, respectively. Since the closing system inaccordance with the application provides a simply conceivedself-regulation, implantation into the human body is also safe.Moreover, it is possible to manually control miction via thiseasy-to-operate closing system, with the control of the closing systemalso being possible automatically by tapping the neurological signalsdirectly on the body organ's nerve path in case of the urethra of theureteral sphincter, by means of an artificial synapse. With the closingsystem in accordance with the application, it is moreover possible thatthe energy consumption is kept low due to the simplicity of the closingsystem, thus providing a long service life. With the closing system inaccordance with the application, the patient will regain a large measureof life quality by ensuring his or her continence with this implant andwill not be limited in his or her radius of action since the system ismaintenance-free.

Additional advantageous embodiments of this invention are the subject ofsubclaims.

If the regulating system with the closing element in accordance withClaim 2 is designed as a closed circuit, a separate supply oftransmission medium will not be required, for example hydraulic agents.

With the characteristics presented in Claim 3, the self-regulatingclosing system will be converted in a simple manner so that the closingsystem as such is easy to implant and has only low energy consumption.Self-regulation will particularly be achieved by the alternate openingand closing of the shutoff valves. At this point, however, referenceshould be made here that a quick-action pump or, respectively, aquick-action actuator may be used instead of the pump device and a firstshutoff valve.

To be able to best possibly adjust self-regulation depending on the bodyorgan, i.e. keeping the closing pressure at a specific threshold valueand setting a corresponding working pressure in this respect, differentsensor elements are provided which, in suitable positioning, willoptimally bring about the self-regulating measure.

Additional advantageous embodiments are the subject of the remainingsubclaims.

On the basis of the following drawing, a preferred embodiment of thesubject of the application will be described.

FIG. 1A shows the closing system which, in this case, selectively opensand closes a urethra as the body organ. With the closing system inaccordance with the application, the urethra has a closing element 1which is hydraulically controllable in this embodiment. Incidentally, itis pointed out that any other control is also conceivable. A regulatingsystem 3—in this case hydraulic—is connectable to the closing element 1.The regulating system 3 serves to adjust a first condition of theclosing system, for example a closing condition of the closing element1. For this, the regulating system 3 in its hydraulic design has a firstreservoir 5 to build up, via a pump device 7, a specific pressure, aso-called closing pressure on the closing element 1. The connecting linearriving at the closing element divides into a first feed line Z1 and asecond feed line Z2, with the first feed line having the pump device 7and advantageously a first shutoff valve V1, and the second feed linehaving a second shutoff valve V2, with the first feed line as well asthe second feed line being connected with the first reservoir 5.Conventionally, the closing system according to the application can alsomerely be used as a device for the selective opening and closing of abody organ, in this case the urethra. To operate the selective openingand closing, it is advantageous that the pump device 7, the firstshutoff valve V1 and the second shutoff valve V2 are connected with acontrol unit 11 which takes over the conventional opening and closing ofthe closing element 1. The closing system according to the applicationfurthermore has a first sensor unit S1, which is provided on the closingelement 1 preferably upstream of the tubular body organ, also a secondsensor unit S2 which measures the pressure in the connection line and athird sensor unit S3 on the pump device 7. This enables a differentialpressure measurement.

The closing system according to the application now works according tothe following functional principle.

The pump device 7 avails itself from the reservoir 5 as the feed supplyand produces a closing pressure on the closing element 1 which isselected such that the closing pressure seals the body organ via theclosing element, however, does not impair the blood circulation in thebody organ. The closing pressure is equivalent to a pressure range whichdepends on various parameters, such as e.g. body organ, vessel gauge,blood circulation intensity, etc.

In case of a short-term pressure increase in the body organ, for examplewith the urethra in the urinary bladder, due to coughing, sneezing,laughing or other exertion, the closing pressure is not sufficient andthere would be a short-term flow-through in the body organ. In thiscase, it is of advantage if the closing pressure will also increaseshort-term to thus further maintain the seal of the body organ. Theshort-term increase of the closing pressure caused in the closing systemaccording to the application will, however, not lead to any necrosisformation, i.e. the blood circulation in the body organ will be affectedfor only a short time and will thus not be damaging for the body organ.To maintain this mechanism, it is necessary that the regulating system 3has different pressure ranges. In the embodiment presented in FIG. 1A,the pump device 7 which is, for example, designed as a quick-action pumpor even as a fast actuator will generate the required closing pressurevia the first shutoff valve V1. To this end, the second shutoff valve V2must be closed. When reaching the closing pressure, the first shutoffvalve V1 is closed, with the pump device 7 building up to the firstshutoff valve V1 a working pressure which is increased versus theclosing pressure.

Should flow-through be effected through the body organ with the closingelement, merely the second shutoff valve V2 must be opened to reduce theclosing pressure via reservoir 5. If there are, however, upstream of theclosing element 1 pressure peaks or, respectively, short-term sustainedpressure loads, they will be registered or, respectively, recorded withthe sensor device S1 and transmitted to the control unit 11. The controlunit 11 opens nearly simultaneously the first shutoff valve V1 so thatthe increased working pressure is applied to the closing element 1 andthus ensures, short-term, that the body organ is also sealed versuspressure peaks. It is here conceivable that, depending on thecirculation function of the body organ, the control unit 11, after atime constant, will close the first shutoff valve again and opens thesecond shutoff valve to regulate the increased working pressure down tothe required closing pressure. Simultaneously or intermediately, thepump device 7 can again build up an increased working pressure which isapplied to the first working valve V1 and thus preparing itself for asecond action.

Thus, the regulating system 3 according to the application is able, inthis manner, to return from a first condition of the closingsystem—which can conventionally be compared with the closing of the bodyorgan via the closing element 1 via the selective opening—any deviationof the first condition back to the first condition in a self-regulatingmanner. This measure achieves that the closing system will meet the taskof the closing system in any situation, thus also in case of strains,such as coughing or sneezing. Since the closing pressure is adjusted, bymeans of a fine sensory control, to the pressure prevailing upstream inthe body organ or, respectively, the bladder pressure in the urinarybladder, necrotic manifestations will be prevented which will normallybe caused by a constantly high closing pressure which suppresses theblood circulation in the body organ and thus causes long-term damage.

At this point, it should once again be emphasized that—as shown in FIG.1A—the pump device 7 can also be replaced via a normal pump incombination with a second reservoir R2 and a third shutoff valve V3. Inthis case, the working pressure which is increased versus the closingpressure will be reached due to the fact that the pump—with opened thirdshutoff valve—applies pressure to reservoir R2 up to the requiredworking pressure, after which the third shutoff valve V3 will then beclosed. This measure will achieve that the use of a quick-action pumpwill not be required since the short-term application of pressure on theclosing element 1—upon occurrence of pressure peaks in excess of theworking pressure built up in the second reservoir R2—is applied to theclosing element by opening the first shutoff valve.

Basically, it should be made clear that the sensor elements are notmerely considered as pressure sensors, but that the pressure can also bedetermined with capacitive or inductive sensors, with volume changesalso able to be measured via ultrasound or via foil strain gauges, or achange in distance resulting with a pressure increase being measured bylight.

According to another aspect, this invention relates to a method for theelectronic control of an artificial fine-sensory sphincter implant,especially to avoid strain incontinence and necrosis on the urethra, anda system for the electronic control of an artificial fine-sensorysphincter implant. Through this invention, the hitherto existing systemof an artificial sphincter implant, expanded by a fine sensory systemand an actuator system, is to be controlled such that not only completecontinence can be ensured but also, at the same time, minimizing therisk of necrosis generated due to pressure which is excessive andapplied for too long to the natural urethra.

Prerequisite for this is an intelligent, electronic control whichrecognizes different strain situations and—by increasing the cuffpressure—will prevent incontinence in case of dynamic strain, such ascoughing or laughing for example, and at the same time, at restconditions, will ensure sufficient blood circulation of the urethratissue through corresponding pressure reductions. Since this electroniccircuitry will be used in a medical implant, it must meet certainrequirements such as reliability over long periods of time, minimumpower consumption, small physical dimensions and individualadaptability.

The additional objective of the invention will follow directly fromthis.

Thus, in accordance with the invention, a method for the electroniccontrol of an artificial fine-sensory sphincter implant will furthermorebe provided, as it is defined in Claim 12.

In accordance with the invention, a system for the electronic control ofan artificial fine-sensory sphincter implant will furthermore beprovided, as it is defined in Claim 25.

Additional advantageous and/or preferable embodiments of the inventionare the subject matter of the subclaims.

In the following, this aspect of the invention will be described in moredetail merely by way of example and without limitation, and withreference to the Figures as well as to advantageous and/or preferredembodiments.

The meaning of the references used is provided in the list below. Theterms of signal and value are here used synonymously.

-   (1) Differential pressure signal, bladder/cuff pressure difference-   (2) Monostable threshold signal, safety threshold-   (3) Bistable threshold signal, normal pressure threshold-   (4) Cuff pressure-   (5) Monostable reference signal, zero integration offset-   (6) Monostable threshold signal, integration threshold-   (7) Admission pressure signal-   (8) Monostable threshold signal, admission pressure threshold-   (9) Dynamic strain-   (10) Monostable threshold signal, pressure compensation threshold-   (11) Internal bladder pressure-   (12) Output signal or, respectively, output value of the adding    function, lower threshold value-   (13) Output signal or, respectively, output value of the integrator    function-   (14) Output signal or, respectively, output value of the    differentiator function-   (15) Increase of cuff pressure-   (16) Decrease of cuff pressure-   (17) Admission pressure-   (18) Increase of admission pressure-   (19) Output signal of the integrator function of the delay block-   (20) Dynamic strain-   (21) Area of retrogressive integration-   (22) Area of progressive integration-   (23) Method for regulating the urethra closing pressure by means of    an inflatable cuff, a fluid reservoir, a pump, and a valve via    hydraulic connections-   (24) Hydraulic connection-   (25) Cuff-   (26) Controllable valve-   (27) Bi-directional pump-   (28) Fluid reservoir-   (29) Admission pressure reservoir-   (30) Method for regulating the urethra closing pressure by means of    an inflatable cuff, a fluid reservoir, a pump, three valves and an    admission pressure reservoir via hydraulic connections-   (31) Urethra closing pressure-   (32) Differentiator function-   (33) Adding function-   (34) Integrator function-   (35) Parameter variation-   (36) Comparator element-   (37) Integrator function of the delay block

The figures show

FIG. 1B: a schematic functional block diagram without admission pressurereservoir and with the output signal of the differentiator function asthe input signal of the integrator function;

FIG. 2: a schematic functional block diagram without admission pressurereservoir and with the output signal of the adding function as the inputsignal of the integrator function;

FIG. 3: a schematic functional block diagram with an admission pressurereservoir and with the output signal of the differentiator function asthe input signal of the integrator function;

FIG. 4: a schematic functional block diagram with an admission pressurereservoir and with the output signal of the adding function as the inputsignal of the integrator function;

FIG. 5 a=FIG. 7 a: with sustained dynamic strain, the pressure curve inthe cuff and in the urinary bladder upon short-term dynamic strain;

FIG. 5 b=FIG. 7 b: with sustained dynamic strain, the signal curve ofthe electronic circuit upon short-term dynamic strain;

FIG. 5 c=FIG. 7 c: with sustained dynamic strain, the signal curve ofthe integrator system with the output signal of the differentiatorfunction as the input signal of the integrator function upon short-termdynamic strain;

FIG. 5 d=FIG. 7 d: with sustained dynamic strain, the signal curve ofthe integrator system with the output signal of the adding function asthe input signal of the integrator function upon short-term dynamicstrain;

FIG. 5 e=FIG. 7 e: with sustained dynamic strain, the switchingconditions for pressure increase and pressure decrease in the cuff incase of short-term dynamic strain;

FIG. 6 a=FIG. 8 a: with sustained dynamic strain, the pressure curve inthe cuff, in the urinary bladder and the admission pressure reservoirupon short-term dynamic strain;

FIG. 6 b=FIG. 8 b: with sustained dynamic strain, the signal curve ofthe electronic circuit upon short-term dynamic strain;

FIG. 6 c=8 c: with sustained dynamic strain, the signal curve of theintegrator system with the output signal of the differentiator functionas the input signal of the integrator function upon short-term dynamicstrain;

FIG. 6 d=FIG. 8 d: with sustained dynamic strain, the signal curve ofthe integrator system with the output signal of the adding function asthe input signal of the integrator function upon short-term dynamicstrain;

FIG. 6 e=FIG. 8 e: with sustained dynamic strain, the switchingconditions for pressure increase and pressure decrease in the cuff uponshort-term dynamic strain;

FIG. 6 f=FIG. 8 f: with sustained dynamic strain, the switchingconditions for pressure increase in the admission pressure reservoir;

FIG. 6 g=FIG. 8 g: with sustained dynamic strain, the course of theintegrator signal for controlling the opening of the valve between cuffand admission pressure reservoir;

FIG. 9 a: the integrator signal with switching threshold upon sustaineddynamic strain;

FIG. 9 b: the input signals of the integrator function with areas ofprogressive (22) and retrogressive (21) integration upon sustaineddynamic strain;

FIG. 10: the method for regulation of the urethra closing pressurewithout admission pressure reservoir;

FIG. 11: the method for regulation of the urethra closing pressure withadmission pressure reservoir;

FIG. 12: the signal curve upon dynamic strain, namely 12 a absolutepressures, 12 b the urethra closing pressure signal with switchingthresholds and 12 c the integrator signal with switching thresholds (or,respectively, integrator system or, respectively, integrator element);and

FIG. 13: a functional schematic presentation of the artificial sphincterimplant.

A digital as well as analog realization of the electronic control of thesphincter implant is possible. This will not basically change the methodfor controlling the sphincter implant which is the subject of thisinvention.

By means of variable parameters, the patient is given the opportunity toindividually adjust the implant behavior to personal requirements. Forparameter variation with analog control, D/A converters are used whoseclock signal is externally generated and can be transmitted viatelemetry.

Operating Mode of the Electronic Control

The electronic control which is the subject of this invention convertsfine-sensory signals, especially the differential pressure betweenurinary bladder and cuff or a comparable differential pressure, intocontrol commands to the actuator system of the implant.

The sensor signals applied on the signal inputs are amplified by meansof amplifier circuitry such that the signals will operate between thelimit values specified by the circuitry.

During operation without dynamic strain, such as for example when calmlysitting or lying down, the cuff pressure (4) operates in a range inwhich the blood circulation of the urethra tissue is ensured, whichcould, however, easily result in incontinence upon an increase of theinternal bladder pressure (11). If the differential pressure signal or,respectively, the differential pressure value (1) increases, the cuffpressure (4) will decrease (16) upon reaching a bistable threshold value(3); if the differential pressure signal or, respectively, thedifferential pressure value (1) drops below the lowered bistablethreshold value (3), the decrease (16) of the cuff pressure (4) will beterminated. For the analog variant, this is done by means of acomparator function which is provided with a hysteresis circuit.

If dynamic strain develops, the actuator system must take over thefunction of a healthy sphincter, that is prevent incontinence in case ofdynamic strain, through active pressure transmission, thus theinvoluntary contraction of the sphincter. Upon a sudden pressureincrease, for example when coughing or laughing, the cuff pressure (4)must be increased within milliseconds. Since incontinence can be assumedat a differential pressure of zero, the actuator system will be causedto increase (15) the cuff pressure (4) if the differential pressuresignal or, respectively, the differential pressure value (1) drops belowa threshold value which is different from zero. Moreover, as aprophylactic measure against a certain inertia of the actuator system,the electronic control system is designed to provide this lowerthreshold value—under which the differential pressure signal or,respectively, the differential pressure value (1) may drop upon mictiononly—with an additive active component. To achieve this, for the analogvariant of the differential pressure signal (1), it is differentiated bymeans of a differentiator circuit, and the output signal or,respectively, the output value (14) of the differentiator function isincreased by the lower threshold value by means of an adding circuit.When using a microprocessor, the sensor signal is numericallydifferentiated by subtracting the current signal value from thepenultimate signal value, and the result, if positive, will be addedwith an offset component. The result serves as the lower threshold value(12). With these measures, it will be achieved that the lower thresholdvalue (12)—upon a sudden increase of the internal bladder pressure(11)—runs counter to the sinking differential pressure signal or,respectively, the differential pressure value (1) and thus enables earlyactivation of the actuator system. For the analog variant, the actuatorsystem is activated by means of a comparator which compares thedifferential pressure signal (1) with the lower threshold value (12).

As soon as the actuator system is activated by the differential pressuresignal (1) falling below the lower threshold value (12), the comparatorfunction is deactivated with the analog variant to avoid an excessivecuff pressure (4) in non-strained operation, and the cuff pressure (4)is increased to a value at which continence can be ensured, yet theblood circulation of the urethra tissue concerned may be impaired.

Depending on the design of the actuator system, this pressure increasemay be implemented in different ways:

When using an admission pressure reservoir (29), a valve (26) is openedso that a pressure compensation can take place between the admissionpressure reservoir (29) and the cuff (25). Due to the fluid flow withthis pressure compensation, the admission pressure (17) set beforehandmust be higher by a certain amount than the desired maximum cuffpressure, depending on the design of the cuff (25) and the admissionpressure reservoir (29). The valve between the admission pressurereservoir (29) and the cuff (25) is opened time-controlled. With theanalog variant, an integrator element can here be especially used whichis started simultaneously with the opening of the valve and whose outputsignal (19) is compared by means of a comparator element with amonostable threshold value (10). When reaching parity, the valve (26)between the admission pressure reservoir (29) and the cuff (25) will beclosed again and, at the same time, the increase (18) of the admissionpressure (17) is started in the admission pressure reservoir (29).Activation of the integrator element which—for the analogvariant—controls the decrease (16) of the cuff pressure (25), occurseither simultaneously with the opening or with the closing of the valve(26) between the admission pressure reservoir (29) and the cuff (25).The signal causing the valve (26) between the admission pressurereservoir (29) and the cuff (25) to close will trigger the increase (18)of the admission pressure (17) in the admission pressure reservoir (29).The pressure signal of the admission pressure (17) which is additionallyrequired with the application of an admission pressure reservoir (29)will be compared—for the analog variant—with a monostable thresholdvalue (8) by means of a comparator element and, in case of parity, asignal is triggered which causes termination of the increase (18) of theadmission pressure (17). When a microprocessor is used, it will beprogrammed such that it will principally act like the described analogcircuit.

With a differently designed actuator system without admission pressurereservoir (29), reaching this safety pressure will be registered bymeans of a comparator element or, respectively, a comparator functionwhich compares the differential pressure signal or, respectively, thedifferential pressure value (1) with a monostable threshold value (2)and will trigger a signal when the differential pressure signal or,respectively, the differential pressure value (1) exceeds this thresholdvalue (2) which causes the actuator system to terminate the increase(15) of the cuff pressure (4) . Moreover, this signal activates theintegrator element or, respectively, the integrator function whichcontrols the decrease (16) of the cuff pressure (4).

Activation of the integrator element which controls—for the analogvariant—the decrease (16) of the cuff pressure (4) can in particular bedone via the interruption of a discharge circuit of the condenser withnegative feedback operational amplifier of the integrator element. Thus,integration can take place and the starting value is equivalent to thetension over the discharged condenser.

The electronic circuitry's intelligence is especially manifest in thatthe decrease (16) of the cuff pressure (4) will be delayed uponsustained dynamic strain. For the analog variant, an integrator elementis used for this. A suitable selection of the input signals will achievethat—in case of short-term strain, for example when getting up from asitting position—the cuff pressure (4) is relatively fast decreasedagain to values which correspond with a safe normal operation withoutthe risk of necrosis. In contrast, with sustained dynamic strain—forexample with physical activities—the cuff pressure (4) is kept so longat a high level until the dynamic strain abates. With the analogvariant, this behavior is generated by applying two suitable signals onthe inverting and non-inverting input of the operation amplifier of theintegrator element. On the one hand, this is a signal which is analog tothe output signal (14) of the differentiator element, especially eitherthe output signal (14) of the differentiator element itself or theoutput signal (12) of the adding element. At the other input of theoperation amplifier of the integrator element, there is a monostablereference signal (5). This monostable reference signal (5) is selectedsuch that it can be crossed by the signal applied at the other input ofthe operation amplifier of the integrator element upon dynamic strainand thus volatile output signal (14) of the differentiator element. Thiscircuiting of the integrator element has the consequence that the outputsignal (13) of the integrator element moves away from the starting pointif the input signal which is analog to the output signal (14) of thedifferentiator element has not or rarely crossed the monostablereference signal (5), thus in case of a low dynamic of strain. Incontrast, however, if the dynamic of strain is high, the input signalanalog to the output signal (14) of the differentiator elementfrequently crosses the monostable reference signal (5). As soon as theinput signal analog to the output signal (14) of the differentiatorelement has crossed the monostable reference signal (5), the outputsignal (13) of the integrator element moves toward the starting value.Thus, with a high dynamic of strain, the output signal (13) of theintegrator element is driven in zigzag fashion toward the startingvalue. For the analog variant, a comparator element will compare theoutput signal (13) of the integrator element with a constant thresholdvalue (6) which may not be in the proximity of the starting value of theoutput signal (13) of the integrator element. As soon as the outputsignal (13) of the integrator element reaches this constant thresholdvalue (6), a decrease (16) of the cuff pressure (4) is caused. Thisdecrease occurs due to the activation of the comparator element whichcauses the actuator system to decrease (16) the cuff pressure (4) untilthe differential pressure signal (1) falls below the lowered bistablethreshold signal (3). The cuff pressure (4) is now again in a safe rangewhere the risk of necrosis is minimal. If a microprocessor is used, itwill basically perform numerically the same calculations as the analogcircuit and will thus produce a comparable behavior.

Another vital characteristic of this electronic control is the presenceof a plurality of possibilities to influence the system's behavior fromthe outside through a variation of parameters. The artificialfine-sensory sphincter implant can thereby be adjusted to the patient'sindividual requirements—on the one hand, setting the parameters afterscarring is completed after the implantation; on the other hand, in caseof changing requirements by the patient, for example with progressingage or a changed way of life.

Since, for the analog variant, the number of variable parameters must belimited as opposed to the digital variant, four parameters have beenselected for the variation which can decisively influence the behaviorof the implant.

The Monostable Offset Signal

The monostable offset signal is the additive component which supplementsthe output signal (14) of the differentiator element to the lowercircuit threshold. By variation of the monostable offset signal, anexcessively sluggish actuator system or a premature urine flow can becompensated.

The Bistable Threshold Signal (3)

The bistable threshold signal (3) can be varied if the cuff pressure (4)in normal operation already reaches critical values for the bloodcirculation of the urethra tissue, or if the bistable threshold signal(3) is adjusted so low that the decrease (16) of the cuff pressure (4)is caused unreasonably frequently.

The Monostable Reference Signal (5)

By variation of the monostable reference signal (5), the speed ofintegration can be adjusted.

The Monostable Threshold Signal (2)

The monostable threshold signal (2) is equivalent to the differentialpressure signal or, respectively, the differential pressure value (1) atwhich the cuff pressure (4) has a value which ensures continence, wherethe blood circulation of the urethra tissue is impaired, however. If themonostable threshold signal (2) is too low, the differential pressuresignal or, respectively, the differential pressure value (1) can fallbelow the lower circuit threshold—despite increased cuff pressure (4) incase of a high dynamic strain—and thus trigger a further pressureincrease. With a monostable threshold signal (2) which is adjusted toohigh, the urethra tissue may be damaged due to the excessive cuffpressure (4);

or

The Monostable Threshold Signal (8)

By variation of the monostable threshold signal (8), the admissionpressure in the admission pressure reservoir and thus the maximum cuffpressure (4) is adjusted after pressure compensation.

If a microprocessor is used, there are considerably more possibilitiesfrom the start to influence the behavior, including a completely newprogramming.

The Methods for Regulation of the Cuff Pressure

The actuator system controlled by the described analog circuit can availitself of various methods and arrangements to produce the desiredinfluence on the urethra. The different arrangements and components ofthe actuator system require matched control electronics. Two hydraulicmethods are described hereinafter by way of example—one with and onewithout an admission pressure reservoir (29).

See FIG. 10, with regard to the method for a regulation of the cuffpressure (4) by means of a pump (27), a valve (26) and a fluid reservoir(28) via hydraulic connections (24).

With this method for a regulation of the cuff pressure (4), use of apump (27) is specified which, upon standstill, puts up slight resistanceto the hydraulic flow. Upon opening the valve (26) to decrease (16) thecuff pressure (4), there is a pressure compensation between the cuff(25) and the fluid reservoir (28). The valve (26) can be placed betweenthe cuff (25) and the pump (27), as well as between the pump (27) andthe fluid reservoir (28).

See FIG. 11, with regard to the method for a regulation of the cuffpressure (4) by means of a pump (27), an admission pressure reservoir(29), three valves (26) and a fluid reservoir (28) via hydraulicconnections (24).

The use of an admission pressure reservoir (29) in this method enables aflash-like increase (15) of the cuff pressure (4). However, anotherpressure sensor will be required which controls the regulation of theadmission pressure (17). After triggering the increase (15) of the cuffpressure (4), a pressure compensation will be enabled by opening thevalve (26) between the admission pressure reservoir (29) and the cuff(25). Thus, the safety pressure in the cuff (25) only depends on theadmission pressure (17) adjusted beforehand in the admission pressurereservoir (29). Also decisive for the pressure compensation is thedesign of the admission pressure reservoir (29). The smaller thedimensions, the larger the admission pressure (17) must be.

Since for the increase (18) of the admission pressure (17), the periodafter the increase (15) of the cuff pressure (4) is used—thus, nofurther increase (15) of the cuff pressure (4) can be triggered for acertain period of time—when selecting the pump (27), there need not beany high speed requirements. This will enable operation at low voltages.

Miction Control

To begin miction, a signal is generated externally. This signal causesthe actuator system to decrease (16) the cuff pressure (4) and,moreover, it deactivates the analog electronic circuit except for thecomparator element which limits the normal cuff pressure to the top.

After termination of miction, a second external signal is generatedwhich again initiates the increase (15) of the cuff pressure (4). Thecuff pressure (4) will be increased until the differential pressuresignal or, respectively, the differential pressure value (1) reaches thebistable threshold value (3). By means of a comparator, the remaininganalog electronic circuit will thus be reactivated.

In summary, this aspect of the invention thus comprises the followingembodiments:

According to embodiment 1, the method for the electronic control of anartificial fine-sensory sphincter implant is characterized in that thebehavior of at least one sensor signal in an analog or digitalelectronic circuit will be converted such by means of calculator andcomparator functions and compared with reference values such that anactuator system will be controlled such that the cuff pressure or,respectively, the differential pressure between the cuff and the urinarybladder will move either in a low range, limited by two thresholdvalues, or above a specific safety pressure.

According to embodiment 2, the sensor signal or, respectively, thesensor value (1) of the electronic circuit according to embodiment 1 ischaracterized in that it behaves analog the difference between theinternal bladder pressure (11) and the cuff pressure (4).

According to embodiment 3, the differentiator function of the electroniccircuit according to embodiment 1 is characterized in that the outputsignal or, respectively, the output value (14) of the differentiatorfunction is in accordance with the differentiation of the course of thesensor signal (1) according to embodiment 2.

According to embodiment 4, the adding function with a monostable offsetsignal or, respectively, offset value of the electronic circuitaccording to embodiment 1 is characterized in that the output signal or,respectively, the output value (12) of the adding function is inaccordance with the output signal or, respectively, output value (14) ofthe differentiator function according to embodiment 3, increased by amonostable offset signal or, respectively, a monostable offset value.

According to embodiment 5, the comparator function with a bistablethreshold signal or, respectively, threshold value (3) of the electroniccircuit according to embodiment 1 is characterized in that—in the eventof parity or, respectively, crossing of the sensor signal or,respectively, the sensor value (1) according to embodiment 2 with thebistable threshold signal or, respectively, with the bistable thresholdvalue (3)—this threshold signal or, respectively, this threshold value(3) will be decreased or, respectively, increased by the amount due tohysteresis and a signal will be triggered which causes the actuatorsystem to decrease (16) the cuff pressure (4) until a signal istriggered—due to the renewed parity or, respectively, renewed crossingof the sensor signal (1) according to embodiment 2 with the bistablethreshold signal or, respectively, the bistable threshold value—whichcauses the actuator system to terminate the decrease (16) of the cuffpressure (4) and will increase or, respectively, decrease the bistablethreshold signal or, respectively, the bistable threshold value (3) bythe amount due to hysteresis.

According to embodiment 6, the comparator function of the electroniccircuit according to embodiment 1 is characterized in that the sensorsignal or, respectively, the sensor value (1) according to embodiment 2is compared with the output signal or, respectively, the output value(12) of the adding function according to embodiment 4 such that—in theevent of parity or, respectively, crossing of the sensor signal or,respectively, the sensor value (1) according to embodiment 2 with theoutput signal or the output value (12) of the adding function accordingto embodiment 4—a signal will be triggered which causes the actuatorsystem to increase (15) the cuff pressure (4) and deactivates thecomparator function according to embodiment 5.

According to embodiment 7, the integrator function with a monostablereference signal or, respectively, a monostable reference value (5) anda constant starting value of the electronic circuit according toembodiment 1 is characterized in that optionally

a) the monostable reference signal or, respectively, the monostablereference value (5) is unequal to the monostable offset signal or,respectively, the offset value according to embodiment 4 and is selectedsuch that the output signal or, respectively, the output value (12) ofthe adding function according to embodiment 4 upon activity will crossthe monostable reference signal or, respectively, the monostablereference value (5), and that the integrator function will continuouslyor numerically integrate the difference between the output signal or,respectively, the output value (12) of the adding function according toembodiment 4 and the monostable reference signal or, respectively, themonostable reference value (5) such that with a low activity of theoutput signal or, respectively, the output value (14) of thedifferentiator function according to embodiment 3, the output signal or,respectively, the output value (13) of the integrator function will moveaway from the starting value and upon high activity of the output signalor, respectively, the output value (14) of the differentiator functionaccording to embodiment 3, will move toward the starting value, see FIG.1 d, FIG. 2 d, FIG. 3 d, FIG. 4 d and FIG. 5; or

b) the monostable reference signal or, respectively, the monostablereference value (5) is unequal to the output signal or, respectively,the output value (14) of the differentiator function according toembodiment 3 upon low activity and is selected such that the outputsignal or, respectively, the output value (14) of the differentiatorfunction according to embodiment 3 upon activity will cross themonostable reference signal or, respectively, the monostable referencevalue (5), and that the integrator function will continuously ornumerically integrate the difference between the output signal or,respectively, the output value (14) of the differentiator functionaccording to embodiment 3 and the monostable reference signal or,respectively, the monostable reference value (5) such that, upon lowactivity of the output signal or, respectively, the output value (14) ofthe differentiator function according to embodiment 3, the output signalor, respectively, the output value (13) of the integrator function willcontinuously move away from the starting value and upon high activity ofthe output signal or, respectively, of the output value (14) of thedifferentiator function according to embodiment 3 will move towards thestarting value, see FIG. 1 c, FIG. 2 c, FIG. 3 c, FIG. 4 c and FIG. 5.

According to embodiment 8, the delay function of the electronic circuitaccording to embodiment 1 when using a method for the regulation of thecuff pressure (4) with admission pressure reservoir (29) ischaracterized in that, upon triggering the pressure compensation betweenthe admission pressure reservoir (29) and the cuff (25) by thecomparator function according to embodiment 6, the delay function willbe activated and upon reaching the set delay time, a signal is triggeredwhich causes the actuator system to terminate the pressure compensationbetween the admission pressure reservoir (29) and the cuff (25) andactivates the integrator function according to embodiment 7 such that,upon activation, the output signal or, respectively, the output value(13) of the integrator function according to embodiment 7 is inaccordance with the constant starting value according to embodiment 7.

According to embodiment 9, the comparator function with a monostablethreshold signal or, respectively, threshold value (2) of the electroniccircuit according to embodiment 1 is characterized in that—in the eventof parity or, respectively, crossing of the sensor signal or,respectively, sensor value (1) according to embodiment 2 with themonostable threshold signal or, respectively, the monostable thresholdvalue (2)—a signal is triggered which causes the actuator system toterminate the increase (15) of the cuff pressure (4) and activates theintegrator function according to embodiment 7 such that, uponactivation, the output signal or, respectively, the output value (13) ofthe integrator function according to embodiment 7 will be in accordancewith the constant starting value according to embodiment 7.

According to embodiment 10, the comparator function with a monostablethreshold signal or, respectively, a monostable threshold value (6) ofthe electronic circuit according to embodiment 1 is characterized inthat—in the event of parity or, respectively, crossing of the outputsignal or, respectively, the output value (13) of the integratorfunction according to embodiment 7 with the monostable threshold signalor, respectively, threshold value (6)—a signal is triggered which causesthe actuator system to decrease (16) the cuff pressure (4) and/oractivates the comparator function according to embodiment 5.

According to embodiment 11, the monostable offset signal or,respectively, the monostable offset value according to embodiment 4 ischaracterized in that it can be varied by parameter variation from theoutside.

According to embodiment 12, the bistable threshold signal or,respectively, the bistable threshold value (3) according to embodiment 5is characterized in that it can be varied by parameter variation fromthe outside.

According to embodiment 13, the monostable reference signal or,respectively, the monostable reference value (5) according to embodiment7 is characterized in that it can be varied by parameter variation fromthe outside.

According to embodiment 14, the monostable threshold signal or,respectively, the monostable threshold value (2) according to embodiment9 is characterized in that it can be varied by parameter variation fromthe outside.

According to embodiment 15, the method of the electronic circuit for thecontrol of miction according to embodiment 1 is characterized in that,for activation of miction, an external signal causes the actuator systemto decrease the urethra closing pressure and deactivates the electroniccircuit according to embodiment 1 expect for the comparator functionaccording to embodiment 5, and for deactivation of miction, an externalsignal causes the actuator system to increase (15) the cuff pressure (4)until a signal is triggered—in the event of parity or, respectively,crossing of the sensor signal (1) according to embodiment 2 with thebistable threshold signal or, respectively, threshold value (3)according to embodiment 5—which activates the electronic circuitaccording to embodiment 1.

This invention presents a novel fine-sensory implant which combines themost important aspects of technological issues of in vivo medicaltechnology: a reliable fine sensory system; intelligent, flexiblecontrol electronics with low power consumption; a miniaturized andpowerful actuator system, as well as sophisticated energy and datatransmission. Using this implant as an example—an artificial, adaptive,fine-sensory sphincter—the current state of the art of implantationtechnology will be discussed before the background of its developmenthistory and the methodical development of criteria for selection controland alternative design, including intensive tests for the determinationof individual components, simultaneously taking comparable implants intoaccount.

Numbers in brackets refer to the places found in the bibliography at theend of this description. The references refer to FIGS. 12 a to 12 c.

A current system of an artificial bladder neck sphincter, for examplethe AMS 800, uses a hand pump in the scrotum or, respectively, the labiamajora, which is used to pump up the collar which blocks the flow ofurine and is placed around the urethra [6]. The setting of the urethraclosing pressure is problematical with this system. Insufficientpressure results in involuntary discharge of urine upon dynamic strainwhich can be caused by laughing, coughing, sneezing or heavy lifting.Excessive pressure on the urethra over a long period of time can readilyresult in black tissue, i.e. necrosis. To avoid this risk, the practicehas so far been to rather accept a slight strain incontinence with allits negative social consequences.

The artificial fine-sensory sphincter implant which has been developedin accordance with the invention replaces the hand pump by activehydraulics, equipped with a fine sensory system and intelligentcontrols. This system can support or replace active pressuretransmission. The sensory system primarily monitors the differencebetween internal bladder pressure and cuff pressure. In case of dynamicstrain, the actuator system is used to increase the cuff pressure sothat continence will be ensured even at these increased pressureconditions. Normal blood circulation of the urethra tissue can therebybe impaired for a short term. The implant is able to distinguish betweensingle-action strain and sustained dynamic strain.

Control

The decisive factor for the function of the artificial fine-sensorysphincter implant is the urethra closing pressure (31). If the urethraclosing pressure (31) is negative, urine discharge will occur.

The signal which is equivalent to the urethra closing pressure (31) isascertained from the two absolute pressure signals of the cuff (25) andthe urinary bladder (FIG. 12 a). In case of suddenly arising dynamicstrain in the peritoneal cavity, this signal goes fast toward zero. Toensure a fast reaction of the implant in this situation, the followingmeasures are taken:

Lowering of the urethra closing pressure (31) is limited toward thebottom by a switching threshold which is above the incontinence rangeand can be varied in programming.

The response of the urethra closing pressure (31) will be differentiatedand the positive portion added to the lower switching threshold (12).The faster the urethra closing pressure (31) decreases, the sooner theimplant's actuator system will be activated on the basis of this measure(t₁ (FIG. 12 b).

This time-critical area is realized by means of analog electroniccomponents to enable maximum reaction speed. The actuator system isactivated by means of a comparator which compares the signal of theurethra closing pressure (31) with the lower switching threshold (12).

The use of an admission pressure reservoir enables a flash-like reactionof the actuator system with little supply voltage. After termination ofthe pressure compensation (t₂), the admission pressure (17) is increasedto a variable maximum value p_(max) (within t₂ to t₃).

After termination of the dynamic strain, the increased cuff pressure isdecreased, microprocessor-controlled, under the normal pressurethreshold (3) provided with a hysteresis. To obtain a measure for thedynamic strain, the difference of an offset value (5) which can also bevaried in programming, and the lower switching threshold (12) will beintegrated. Thus, with a sustained dynamic strain, the integrationresult (13) is pressed downwardly in zigzag shape. Without dynamicstrain, the integration result (13) increases up to a threshold value(6), and when this is reached, the reduction of the cuff pressure willbe triggered (t₄) (FIG. 12 c).

The normal pressure threshold prevents an excessive cuff pressure innormal operation. Like the activation of the actuator system, thisfunction will also be realized with analog electronic components.

The analog circuit comprises 4 variable parameters which are influencedby means of D/A converters, namely: the speed of differentiation of theurethra closing pressure signal, the additive offset component of thelower threshold value, as well as the mean value and the hysteresis ofthe normal pressure threshold. Thus, the permanently activatedelectronics will be limited to a minimum of 6 operation amplifiers and aquad-digital potentiometer of the analog circuit, as well as to thesignal conditioning and the RF receiver module. The electronics completepower consumption is under 0.1 mW, with the microprocessor in power-downmode.

Programming Software

The artificial fine-sensory sphincter implant according to the inventionis programmed by means of an external programming station. Via abi-directional transcutaneous data transfer, the urethra closingpressure as well as the absolute pressure in the admission pressurereservoir are transmitted into the programming station. The in vivopressure measurement, in combination with a simultaneous externalurodynamic examination enables largely automated implant programming.The patient performs defined physical actions; for example, getting upfrom a sitting position or coughing. From the collected measuring datatogether with empirical values from clinical tests, the software canevaluate an optimal setting of the implant. Subsequently requiredadjustments of the programming are also manually possible, for examplewith regard to the patient's changed living conditions or a changedbehavior of the implanted electronics.

Sensory System

Proper functioning of the artificial sphincter implant requires the useof three pressure sensors which must measure the pressure at differentplaces and with different prerequisites:

In the admission pressure reservoir, use of a surface sensor suggestsitself which can be integrated into the rigid base plate of theadmission pressure reservoir. This capacitive pressure sensor consistsof a polysilicon membrane and a silicon substrate [1]. Duringmanufacture, a vacuum is produced between the polysilicon membrane andthe silicon substrate so that an absolute pressure sensor is developed.With the minor diameter of 100-120 μm of a sensor element, a sensorarray connected in parallel can be set up for signal amplification [2].

When using an absolute pressure sensor in the admission pressurereservoir, the absolute pressure in the cuff can also be measured bymeans of a differential pressure sensor which measures the differencebetween cuff and admission pressure. By means of a suitable electroniccircuit, the absolute pressure signal of the cuff pressure can befiltered from the absolute pressure signal of the admission pressurereservoir and the differential pressure signal between cuff andadmission pressure reservoir. This enables the use of an inexpensive andreliable piezo-resistive differential pressure sensor which is connectedvia hydraulic connections with the admission pressure reservoir as wellas with the cuff.

To measure the internal bladder pressure, an absolute pressuresensor—similar to a brain pressure probe—is embedded in the tissue inthe vicinity of the bladder so that the urinary bladder need not bepunctured or opened [5]. The measured pressure will possibly not beexactly the same as the internal bladder pressure but it will beequivalent.

Electronics

In the artificial sphincter implant, the physical dimensions as well asthe power consumption of the electronic components are not the criticalparameters since both are negligible in comparison with the propertiesof the actuator system. Nonetheless, minimization is aimed at althoughmore importance may be attached to reliability and redundant systems.

With regard to the requirements, the control electronics specified forthe artificial fine-sensory sphincter implant are similar to those of amodern pacemaker. As in a pacemaker, sensor signals from amicroprocessor are analyzed and converted into implant actions. Tominimize the electronics power consumption, the microprocessor isnormally operated in power-down mode. The comparator which activates theactuator system upon dynamic strain simultaneously activates themicroprocessor.

The use of a microprocessor programmable via transcutaneous datatransmission has the fundamental advantage that it can flexibly react toany changes, for example in the patient's habits or in the behavior ofelectronic components. The use of analog semiconductor components, forexample as a calculator circuit to determine the absolute cuff pressure,will thus be less critical.

With a power consumption of under 1 μA per operation amplifier, theanalog components can be permanently activated without any problem. Theonly intermittently active microprocessor can be operated withrelatively high clock frequencies since the connected relatively highpower consumption can be easily compensated by a considerably improvedperformance of the implant.

While a condenser charged with up to 1 kV must be operated with apacemaker (usually by means of IGBTs) which discharges via the humantissue between the electrodes with several ten amperes within severalmilliseconds, for the artificial fine-sensory sphincter implant, maximumpermanent currents of approx 100 mA per switch must be operated at asupply voltage of 4.2 V. MOSFETs suggest themselves for this purposewhich can be directly operated from the microprocessor. To ensurereliability, several MOSFETs are switched in parallel per switch unit sothat the switching duty can still be handled without problems ifindividual components fail. They can be integrated in a multi-chipmodule (MCM).

The signal conditioning, the analog circuit, the A/D converter, theinternal memory and the microprocessor with a multi-I/O module can becombined in a mixed signal ASIC, an application-specific integratedcircuit [4]. This offers extremely low power consumption since—incontrast to the use of a commercial microprocessor—no unused featureslie fallow yet still use power. This advantage is confronted with highdevelopment expenditures which lead to the desired result via design,simulation and manufacturing. For this reason, the implant prototype isrealized with a commercial microcontroller. The development of an ASCIfor a prototype would be a disproportionately high expenditure of timeand finances.

As a rule, the source of energy is a lithium-ion accumulator which ischarged via a subcutaneously implanted induction coil. The chargecontroller of the lithium-ion battery pack is a commercial IC as it isused for example in mobile phones. It monitors the current flow betweenthe energy transfer module and the battery which it can influence with aMOSFET. Termination, abort and fault will be reported to themicroprocessor.

Actuator system

The miniaturization of implantable actuator systems requires componentscomplying with the high requirements of modern medical technology, suchas bio-compatibility, long life and reliability. In implantationmedicine, silicones and polyurethanes are among the most frequently usedmaterials which are distinguished for their compatibility with the humanbody. Mechanical as well as thermal endurance tests demonstrated thatsilicones and polyurethanes have absolutely equivalent properties. Withmore than 5 million load cycles, their durability for use in humans wassimulated and confirmed.

The actuator system of the artificial fine-sensory sphincter implantconsists of electrically active components, the valves and the pump, andof passive components, an admission pressure chamber, an inflatable cuffand the hydraulic connections (FIG. 13). These components must bespecially adapted for use in the artificial fine-sensory sphincterimplant. Industrial pumps and valves are mostly designed for pressuresof 10 bar and more. Since maximum pressures of under 500 mbar occur inthe implant, adjusted dimensioning of these components makes good sense.

The admission pressure reservoir consists of a rigid base plate overwhich an elastic membrane is stretched. Due to the flat structure, theadmission pressure reservoir can be integrated into the outer shell ofthe implant such that the elastic membrane can bulge outwardly in caseof a pressure increase.

The decisive function of the artificial fine-sensory sphincter implantis the flash-like increase of the cuff pressure in case of a sudden dropin the urethra closing pressure. To keep the time between activation ofthe actuator system and reaching a safe cuff pressure as short aspossible, an increased admission pressure will be provided which can betransmitted to the cuff via valve 3. Since the electronic system reachesreaction times within the microsecond to nanosecond range, the decisivegain in reaction time is to be expected with an optimization of thesystem of admission pressure reservoir, valve 3 and the hydraulicconnection. If, for example, a flow of 0.2 ml will be required toincrease the cuff pressure from 70 mbar to 100 mbar, and the pressuredifference between cuff and admission pressure reservoir is Δp beforethe pressure compensation, the following proportionality will resultwith an opening radius of the hose r (equation 1):$\left. t \right.\sim\frac{1}{{r^{2} \cdot \Delta}\quad{pf}}$

Reaction times of under 10 ms are realizable from activating theactuator system until termination of the pressure compensation. Requiredwill be a pressure difference of Δp=400 mbar and an inside radius of thehydraulic connections of approx. r=1.0 mm. Still shorter reaction timescan be realized with a further enlargement of the inside radius r.

Moreover, the mass inertia of the valve 3 will cause a further delaywhich increases with an increasing opening radius r.

The cuff pressure is reduced via valve 2 in the reservoir. Whendimensioning the valve 2 and the hydraulic connections between cuff andreservoir, care must be taken that the cuff pressure is not reduced toofast. If this is the case, increase of the cuff pressure can beimmediately triggered again due to the valve inertia and the oncominglower switching threshold. However, this risk can be avoided with anappropriate selection of the cross-section opening of the hydraulicconnections.

Energy and Data Transmission

With regard to the energy and data transmission, it has the most thingsin common with the artificial urinary bladder [6] [7] [8]. Other thanfor example with the artificial heart, the energy transmission for theartificial fine-sensory sphincter implant only serves to load theimplanted battery and data transmission is mainly used for programmingthe microprocessor. Moreover, for miction control, another signal pathis used which is uncomplicated to operate for the patient. From theseframework conditions, the following configuration of energy and datatransmission was designed for use in the artificial fine-sensorysphincter implant:

The implanted battery is charged inductively by placing a charger onto asubcutaneously implanted induction coil [3]. To enable fastbi-directional data transmission, an IR sending/receiving module wasplaced in the middle of the induction coil. This optical datatransmission requires—like inductive energy transmission—that theexternal counterpart is placed directly on the skin.

Thus, this function can be integrated into the external charger.

The miction is controlled via unidirectional RF data transmission. Thisenables the patient a comfortable and uncomplicated operation of theimplant. Transmitted will be the miction desire as well as a signal forterminating miction.

Results

By means of a suitable design of the actuator system, as well as anappropriate design of the electronics, a flash-like reaction of thehydraulic system was achieved with the low supply voltage of 4.2 V andthe complex behavior of the electronics with the low power consumptionof under 0.1 mW in the power-down mode of the microprocessor. Thebehavior of the implant is designed so variably that it will be able tomeet a tremendously broad range of requirements.

Bibliography

-   [1] M. Kandler, J. Eichholz, Y. Manoli, W. Mokwa, “CMOS compatible    capacitive pressure sensor with readout electronics”, International    Conference on Micro Electro, Opto, Mechanic Systems and Components,    Micro System Technologies, pp. 574-580, 1990-   [2] H. Dudaicevs, Y. Manoli, W. Mokwa, M. Schmidt, E. Spiegel, “A    fully integrated surface micromachined pressure sensor with low    temperature dependence”, Transducers, Digest of technical papers,    pp. 616-619, 1995-   [3] H. Wassermann, “Drahtlose Energie- und Signalübertragung mit    gleichzeitiger Disloziervorkehrung und -vorrichtung bei    Unzugänglichkeit einer Seite und bei undurchsichtigem Dielektrikum”,    Technisches FB-Kompendium, 1992-   [4] R. Lerch, E. Spiegel, R. Kakerow, R. Hakenes, H. Kappert, H.    Kohlhaas, N. Kordas, M. Buchmann, T. Franke, Y. Manoli, J. Müller,    “A programmable mixed-signal ASIC for data-acquisition systems in    medical implants”, International Solid-State Circuits Conference,    Digest of technical papers, pp. 160-161, 1995-   [5] A. Atala, M. R. Freeman, J. P. Vacanti, J. Shepard, A. B. Retik,    “Implantation in vivo and retrieval of artificial structures    consisting of rabbit and human urothelium and human bladder    muscle”, J. Urol. 150, pp. 608-612, 1993-   [6] D. Jocham and K. Miller “Praxis der Urologie II”, Stuttgart:    Georg Thieme, 1994/2002-   [7] H. Wassermann, “Künstliches harnableitendes System”,    Medizintechnik in Bayern, vol. 2, pp. 57-61, 2002-   [8] R. Stölting, “Künstliche Harnblase—Klinische Tests stehen noch    aus”, medizin report, vol 2, pp. 22-23-   [9] H. Wassermann, “Artificial Urinary Diversion System”, Bavarian    Medical Technologies, vol. 2, pp. 53-57, 2002

1. A closing system, preferably an implantable closing system, for theselective closing and opening of a tubular body organ, comprising aclosing element and a regulating system controlling the closing element,with the regulating system setting a first condition of the closingsystem and returning a deviation from the first condition in aself-regulating manner back to the first condition.
 2. A closing systemaccording to claim 1, with the regulating system together with theclosing element presenting a closed circuit.
 3. A closing systemaccording to any one of the claims 1 or 2, the regulating system havinga first reservoir and sensor elements being in connection with a controlunit, and the connecting line from the closing element dividing into afirst feed line and a second feed line, with the first feed line havinga pump device and a first shutoff valve and the second feed line havinga second shutoff valve between the first reservoir and the closingelement.
 4. A closing system according to any one of the claims 1 to 3,with a sensor element being provided as a first sensor unit on theclosing element, a second sensor unit between the first shutoff valveand the closing element, and a third sensor unit on the pump device. 5.A closing system according to any one of the claims 1 to 4, with thepump device being a quick-action pump.
 6. A closing system according toany one of the claims 1 to 5, with the pump device being a feed pumpwhich is connected with a second reservoir via a third shutoff valve. 7.A closing system according to claim 1, with the regulating systemcontrolling the closing element via a fluid.
 8. A closing systemaccording to any one of the claims 1 to 7, with the sensor units beingpressure sensors.
 9. A process for the selective opening and closing ofa tubular body organ, in particular with the use of the closing systemaccording to any one of the claims 1 to 7 which has the following steps:a) Providing a closing element for the tubular body organs and aregulating system b) Setting a first condition of a closing systemthrough the regulating system c) A self-regulating return of the closingsystem to the first condition in case of a deviation from the firstcondition.
 10. A process according to claim 9, with the first conditionbeing set by providing a reservoir, from which—via a pumpdevice—pressure is applied on the closing element and the pressure isheld on the closing element by closing a shutoff valve.
 11. A processaccording to claim 9 or 10, with a pressure increase in the tubular bodyorgan being registered via a sensor unit and short-term counteracting byincreasing the pressure on the closing element.
 12. A method for theelectronic control of an artificial fine-sensory sphincter implant,characterized in that—in the method—a sensor signal or, respectively,sensor value (1) acting analog to the difference between internalbladder pressure (11) and the cuff pressure (4) in an analog or digitalelectronic circuit, being converted by means of calculator andcomparator functions such and compared with reference values that anactuator system will be controlled such that the cuff pressure or,respectively, the differential pressure between cuff and urinary bladdereither moves in a low range limited by two threshold values or above acertain safety pressure or, respectively, below that in case of miction.13. A method according to claim 12, characterized in that the calculatorfunction of the electronic circuit comprises: (a) a differentiatorfunction whose output signal or, respectively, output value (14) isequivalent to the differentiation of the curve of the sensor signal or,respectively, the sensor value (1); (b) an adding function with amonostable offset signal or, respectively, offset value whose outputsignal or, respectively, output value (12) is equivalent to the outputsignal or, respectively, output value (14) of the differentiatorfunction, increased by the monostable offset signal or, respectively,the monostable offset value; (c) an integrator function with amonostable reference signal or, respectively, a monostable referencevalue (5) and a constant starting value where selectively (i) themonostable reference signal or, respectively, the monostable referencevalue (5) is not equal to the monostable offset signal or, respectively,offset value of the adding function and will be selected such that theoutput signal or, respectively, the output value (12) of the addingfunction upon activity crosses the monostable reference signal or,respectively, the monostable reference values, with the integratorfunction continuously or numerically integrating the difference betweenthe output signal or, respectively, the output value (12) of the addingfunction and the monostable reference signal or, respectively, themonostable reference value (5) such that—upon low activity of the outputsignal or, respectively, the output value (14) of the differentiatorfunction—the output signal or, respectively, the output value (13) ofthe integrator function moves away from the starting value of theintegrator function of the starting value, and in case of high activityof the output signal or, respectively, the output value (14) of thedifferentiator value will move toward the starting value, or (ii) themonostable reference signal or, respectively, the monostable referencevalue (5) is unequal to the output signal or, respectively, the outputvalue (14) of the differentiator function upon low activity and isselected such that the output signal or, respectively , the output value(14) of the differentiator function upon activity will cross themonostable reference signal or, respectively, the monostable referencevalue (5), with the integrator function continuously or numericallyintegrating the difference between the output signal or, respectively,the output value (14) of the differentiator function and the monostablereference signal or, respectively, the monostable reference value (5)such that—upon low activity of the output signal or, respectively, theoutput value (14) of the differentiator function, the output signal or,respectively, the output value (13) of the integrator function willcontinuously move away from the starting value and—upon high activity ofthe output signal or, respectively the output value (14) of thedifferentiator function—will move towards the starting value; (d) acomparator function with a bistable threshold signal or, respectively,threshold value (3), whereby—in the event of parity or, respectively,crossing of the sensor signal or, respectively, sensor value (1) withthe bistable threshold signal or, respectively, the bistable thresholdvalue (3)—this threshold signal or, respectively, this threshold value(3) will be decreased or, respectively, increased by the amount due tothe hysteresis and a signal is thus triggered which causes the actuatorsystem to decrease (16) the cuff pressure (4) until—by renewed parityor, respectively, renewed crossing of the sensor signal (1) with thebistable threshold signal or, respectively, the bistable threshold value(3), a signal will be triggered which causes the actuator system toterminate the decrease (16) of the cuff pressure (4) and increasing or,respectively, decreasing the bistable threshold signal or, respectively,the bistable threshold value (3) by the amount due to the hysteresis;and (e) a comparator function with a monostable threshold signal or,respectively, threshold value (2), whereby—in the event of parity or,respectively, crossing of the sensor signal or, respectively, the sensorvalue (1) with the monostable threshold signal or, respectively, themonostable threshold value (2), a signal is triggered which causes theactuator system to terminate the increase (15) of the cuff pressure (4)and activates the integrator function such that, upon activation, theoutput signal or, respectively, the output value (13) of the integratorfunction is in accordance with the constant starting value.
 14. A methodaccording to claim 13, characterized in that the sensor signal or,respectively the sensor value (1) is compared with the output signal or,respectively, the output value (12) of the adding function such that—inthe event of parity or, respectively, crossing of the sensor signal or,respectively, the sensor value (1) with the output signal or,respectively, the output value (12) of the adding function, a signal istriggered which causes the actuator system to increase (15) the cuffpressure (4) and suspend the comparator function according to claim 13(d).
 15. A method according to claim 13, characterized in that—in theevent of parity or, respectively, crossing of the output signal or,respectively, the output value (13) of the integrator function with themonostable threshold signal or, respectively, threshold value (6), asignal is triggered which causes the actuator system to decrease (16)the cuff pressure (4) and/or activates the comparator function accordingto claim 13 (d).
 16. A method according to any one of the claims 13 to15, characterized in that a delaying function is furthermore providedwhich is activated upon triggering a pressure compensation between anadmission pressure reservoir (29) and a cuff (25) by a comparatorfunction and triggers a signal when reaching the set delay time, whichcauses the actuator system to terminate the pressure compensationbetween the admission pressure reservoir (29) and the cuff (25) andactivates the integrator function such that, upon activation, the outputsignal or, respectively, the output value (13) of the integratorfunction is equivalent to the constant starting value.
 17. A methodaccording to any one of the claims 13 to 16, characterized in that themonostable offset signal or, respectively, the monostable offset valuecan be varied by the parameter variation from the outside.
 18. A methodaccording to any one of the claims 13 to 17, characterized in that thebistable threshold signal or, respectively, the bistable threshold value(3) can be varied by the parameter variation from the outside.
 19. Amethod according to any one of the claims 13 to 18, characterized inthat the monostable reference signal or, respectively, the monostablereference value (5) can be varied by the parameter variation from theoutside.
 20. A method according to any one of the claims 13 to 19,characterized in that the monostable threshold signal or, respectively,the monostable threshold value (2) can be varied by the parametervariation from the outside.
 21. A method according to any one of theclaims 17 to 20, characterized in that the parameter variation iseffected by programming the electronics via infrared transmission fromthe outside.
 22. A method for the control of miction of the electroniccircuit according to any one of the preceding claims 12 to 21,characterized in that—for activation of miction—an external signalcauses the actuator system to decrease the urethra closing pressure anddeactivates the electronic circuit except for the comparator functionaccording to claim 13 (d) and, for deactivation of miction, an externalsignal causes the actuator system to increase (15) the cuff pressure (4)until a signal is triggered which activates the electronic circuit inthe event of parity or, respectively, crossing the sensor signal (1)with the bistable threshold signal or, respectively, threshold value(3).
 23. A method according to claim 22, characterized in that theexternal signal for activation or deactivation of miction is transmittedby infrared transmission or by radio signals or by induction.
 24. Amethod according to any one of the preceding claims 12 to 23,characterized in that the energy supply of the artificial fine-sensorysphincter implant is provided by induction from the outside.
 25. Asystem for the electronic control of an artificial fine-sensorysphincter implant, characterized in that—in the system—at least onesensor signal or, respectively, sensor value (1) behaves analog to thedifference between internal bladder pressure (11) and cuff pressure (4)being converted in an analog or digital electronic circuit by means ofcalculator and comparator elements such and compared with referencevalues such that an actuator system will be controlled such that thecuff pressure or, respectively, the differential pressure between cuffand urinary bladder either moves in a low range limited by two thresholdvalues or above a specific safety pressure or, respectively, below thatin case of miction.
 26. A system according to claim 25, characterized inthat the calculator element of the electronic circuit comprises: (a) adifferentiator element whose output signal or, respectively, outputvalue (14) of the differentiation is equivalent to the curve of thesensor signal or, respectively, the sensor value (1); (b) an addingelement with a monostable offset signal or, respectively, offset valuewhose output signal or, respectively output value (12) is equivalent tothe output signal or, respectively, output value (14) of thedifferentiator element increased by the monostable offset signal or,respectively, the monostable offset value; (c) an integrator elementwith a monostable reference signal or, respectively, a monostablereference value (5) and a constant starting value, wherein selectively(i) the monostable reference signal or, respectively, the monostablereference value (5) is not equal to the monostable offset signal or,respectively, the offset value of the adding element and is selectedsuch that the output signal or, respectively, the output value (12) ofthe adding element upon activity crosses the monostable reference signalor, respectively, the monostable reference value (5), with theintegrator element continuously or numerically integrating thedifference between the output signal or, respectively, the output value(12) of the adding element and the monostable reference signal or,respectively, the monostable reference value (5) such that—upon lowactivity of the output signal or, respectively, the output value (14) ofthe differentiator element—the output signal or, respectively, theoutput value (13) of the integrator element will move away from thestarting value and—upon high activity of the output signal or,respectively, the output value (14) of the differentiator element—willmove towards the starting value, or (ii) the monostable reference signalor, respectively, the monostable reference value (5) is not equal to theoutput signal or, respectively, the output value (14) of thedifferentiator element upon low activity and is selected such that theoutput signal or, respectively, the output value (14) of thedifferentiator element upon activity crosses the monostable referencesignal or, respectively, the monostable reference value (5) with theintegrator element continuously or numerically integrating thedifference between the output signal or, respectively, the output value(14) of the differentiator element and the monostable reference signalor, respectively, the monostable reference value (5) such that—upon lowactivity of the output signal or, respectively, the output value (14) ofthe differentiator element—the output signal or, respectively, theoutput value (13) of the integrator element will continuously move awayfrom the starting value and—upon high activity of the output signal or,respectively, the output value (14) of the differentiator element—willmove towards the starting value; (d) a comparator element with abistable threshold signal or, respectively, threshold value (3),whereby—in the event of parity or, respectively, crossing of the sensor.signal or, respectively, sensor value (1) with the bistable thresholdsignal or, respectively, the bistable threshold value (3)—this thresholdsignal or, respectively, this threshold value (3) is decreased or,respectively, increased by the amount due to the hysteresis and a signalis triggered thereby which causes the actuator system to decrease (16)the cuff pressure (4) until a renewed parity or, respectively, renewedcrossing of the sensor signal (1) with the bistable threshold signal or,respectively, the bistable threshold value (3), a signal will betriggered which causes the actuator system to terminate the decrease(16) of the cuff pressure (4) and increases or, respectively decreasesthe bistable threshold signal or, respectively, the bistable thresholdvalue (3) by the amount due to the hysteresis; and (e) a comparatorelement with a monostable threshold signal or, respectively, thresholdvalue (2) whereby—in the event of parity or, respectively, crossing ofthe sensor signal or, respectively, the sensor value (1) with themonostable threshold signal or, respectively, the monostable thresholdvalue (2) a signal will be triggered which causes the actuator system toterminate the increase (15) of the cuff pressure (4) and activates theintegrator element such that, upon activation, the output signal or,respectively, the output value (13) of the integrator element isequivalent to the constant starting value.
 27. A system according toclaim 26, characterized in that the sensor signal or, respectively, thesensor value (1) is compared with the output signal or, respectively,the output value (12) of the adding element such that—in the event ofparity or, respectively, crossing of the sensor signal or, respectively,the sensor value (1) with the output signal or, respectively, the outputvalue (12) of the adding element, a signal will be triggered whichcauses the actuator system to increase (15) the cuff pressure (4) anddeactivates the comparator element according to claim 26 (d).
 28. Asystem according to claim 26, characterized in that—in the event ofparity or, respectively, crossing of the output signal or respectively,the output value (13) of he integrator element with the monostablethreshold signal or, respectively, threshold value (6), a signal istriggered which causes the actuator system to decrease (16) the cuffpressure (4) and/or activates the comparator element according to claim26 (d).
 29. A system according to any one of the claims 26 to 28,characterized in that furthermore, a delaying element is provided whichis activated upon triggering a pressure compensation between anadmission pressure reservoir (29) and a cuff (25) by a comparatorelement, and upon reaching the set delay period, a signal is triggeredwhich causes the actuator system to terminate the pressure compensationbetween the admission pressure reservoir (29) and the cuff (25) andactivates the integrator element such that, upon activation, the outputsignal or, respectively, the output value (13) is in accordance with theintegrator element of the constant starting value.
 30. A systemaccording to any one of the claims 26 to 29, characterized in that themonostable offset signal or, respectively the monostable offset valuecan be varied by the parameter variation from the outside.
 31. A systemaccording to any one of the claims 26 to 30, characterized in that thebistable threshold signal or, respectively the bistable threshold value(3) can be varied by the parameter variation from the outside.
 32. Asystem according to any one of the claims 26 to 31, characterized inthat the monostable reference signal or, respectively, the monostablereference value (5) can be varied by the parameter variation from theoutside.
 33. A system according to any one of the claims 26 to 32,characterized in that the monostable threshold signal or, respectively,the monostable threshold value (2) can be varied by the parametervariation from the outside.
 34. A system according to any one of theclaims 30 to 33, characterized in that the parameter variation iseffected from the outside by programming the electronics via infraredtransmission.
 35. A system for miction control of the electronic circuitaccording to any one of the preceding claims 25 to 34, characterized inthat—for activating the miction—an external signal causes the actuatorsystem to decrease the urethra closing pressure and deactivates theelectronic circuit except for the comparator element according to claim26 (d), and for deactivation of miction, an external signal causes theactuator system to increase (15) the cuff pressure (4) until—in theevent of parity or, respectively, crossing the sensor signal (1) withthe bistable threshold signal or threshold value (3)—a signal istriggered which activates the electronic circuit.
 36. A system accordingto claim 35, characterized in that the external signal for activation ordeactivation of miction is transmitted via infrared transmission or byradio or by induction.
 37. A system according to any one of thepreceding claims 25 to 36, characterized in that the energy supply ofthe artificial fine-sensory sphincter implant is provided from theoutside by induction.